The invention relates to a method of manufacturing semiconductor devices having a passivated semiconductor body provided with an electrode and fastened on an electrically conducting support body, in which method a slice of semiconductor material is fastened on a surface of an electrically conducting auxiliary slice and mesa structures are formed in the slice of semiconductor material by the application of grooves in the slice of semiconductor material, after which a layer of insulating material is provided on the walls of the grooves, electrodes are provided on upper sides of the mesa structures, and the auxiliary slice comprising the mesa structures is split up at the areas of the grooves into separate semiconductor bodies each fastened on its own support body. The invention also relates to a semiconductor device comprising a semiconductor body fastened on a support body.